Perera, Delwin (2015)
Density functional theory calculations on tilt grain boundaries in graphene.
Technische Universität Darmstadt
Bachelorarbeit, Bibliographie
Kurzbeschreibung (Abstract)
The interest in graphene among researchers has not ceased since Novoselov and Geim published their findings on the electronic properties of graphene in 2004, which was acknowledged with the 2010 Nobel Prize in physics. Many aspects of graphene — electronic, magnetic or mechanic — are not completely understood. Moreover, there are many efforts to develop graphene production methods on large scales for industrial purposes. This can significantly alter graphene’s properties leading to many new problems. In industrial scale graphene production defects such as polycrystallinity are inevitable. There are few studies dealing with the change in behaviour of non-ideal graphene. In this thesis we focus on the piezoresistive properties of non-ideal graphene — i.e. graphene with grain boundaries (GB). We use interatomic potentials and density functional theory to investigate the atomic and electronic structure of different GBs. We find that multiple structures can be obtained from the same tilt angle and we arrange them according to their formation energy. To investigate the piezoresistive properties of non-ideal graphene we compute the density of states and electronic transmission functions applying different compressive and tensile strains. We show that the pentagon-heptagon-ring in Summe7 GBs possesses the lowest formation energy. Further investigation of this GB showed that electric conduction occurs in the compressive regime whereas in the tensile regime virtually no conductance is measured. This behaviour is supported by the atomic density of states where we compare the density of states contribution from GB atoms and bulk atoms. Our results confirm that GBs in graphene play a major role in the electronic transport and that they can be exploited to use graphene as a transparent strain sensor in modern electronics.
| Typ des Eintrags: | Bachelorarbeit |
|---|---|
| Erschienen: | 2015 |
| Autor(en): | Perera, Delwin |
| Art des Eintrags: | Bibliographie |
| Titel: | Density functional theory calculations on tilt grain boundaries in graphene |
| Sprache: | Englisch |
| Referenten: | Albe, Prof. Dr. Karsten ; Krupke, Prof. Dr. Ralph |
| Berater: | Albe, Prof. Dr. Karsten |
| Publikationsjahr: | 28 Juli 2015 |
| Ort: | Darmstadt |
| Datum der mündlichen Prüfung: | 30 Juli 2015 |
| Kurzbeschreibung (Abstract): | The interest in graphene among researchers has not ceased since Novoselov and Geim published their findings on the electronic properties of graphene in 2004, which was acknowledged with the 2010 Nobel Prize in physics. Many aspects of graphene — electronic, magnetic or mechanic — are not completely understood. Moreover, there are many efforts to develop graphene production methods on large scales for industrial purposes. This can significantly alter graphene’s properties leading to many new problems. In industrial scale graphene production defects such as polycrystallinity are inevitable. There are few studies dealing with the change in behaviour of non-ideal graphene. In this thesis we focus on the piezoresistive properties of non-ideal graphene — i.e. graphene with grain boundaries (GB). We use interatomic potentials and density functional theory to investigate the atomic and electronic structure of different GBs. We find that multiple structures can be obtained from the same tilt angle and we arrange them according to their formation energy. To investigate the piezoresistive properties of non-ideal graphene we compute the density of states and electronic transmission functions applying different compressive and tensile strains. We show that the pentagon-heptagon-ring in Summe7 GBs possesses the lowest formation energy. Further investigation of this GB showed that electric conduction occurs in the compressive regime whereas in the tensile regime virtually no conductance is measured. This behaviour is supported by the atomic density of states where we compare the density of states contribution from GB atoms and bulk atoms. Our results confirm that GBs in graphene play a major role in the electronic transport and that they can be exploited to use graphene as a transparent strain sensor in modern electronics. |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Materialmodellierung Zentrale Einrichtungen > Hochschulrechenzentrum (HRZ) > Hochleistungsrechner Zentrale Einrichtungen > Hochschulrechenzentrum (HRZ) Zentrale Einrichtungen |
| Hinterlegungsdatum: | 15 Apr 2016 11:21 |
| Letzte Änderung: | 15 Sep 2016 11:35 |
| PPN: | |
| Referenten: | Albe, Prof. Dr. Karsten ; Krupke, Prof. Dr. Ralph |
| Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 30 Juli 2015 |
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